Pneumatic tool



J. E. FEUCHT PNEUMATIC TOOL Oct. l1, 1960 Filed Feb. 6, 1958 mlm.

Il'lllillaV "nulli III 'lll/11,111

United States Patent PNEUMATIC TOOL Jacob E. Feucht, GarfieldWestinghouse Air Brake a corporation of Pennsylvania Filed Feb. 6, 195s,serpgNo. 113,694 s claims. (ci. 121-32) Heights, Ohio, assignor to Thisinvention relatesV generally to pneumatic tools, such -as clay spadesfand the like, in which compressed air is fed Vinto a cylinder in themachine housing to reciprocate a hammer. The hammer in turn strikes atool which extends from the end of the machine. The air is then portedto the atmosphere.

Conventional tools of this general character have cerltain shortcomings,for example, foreign matter enters the chuck or tool end of the machinewhile the latter is operating to cause malfunctioning. thereof. Anotherobjection to these tools has been the discharge of air which heretoforewas blown toward the operator or adjacent workmen, or was blown towardthe side of the ditch being formed with a resulting spray of dirt overthe area.

In operation these tools are held at their front end by the operator andin certain types of operations the tool a generallycylindricalandelongated housing having Company, Wilmerding, Pa.,

a backhead 11 rigidly secured thereto.- v

Compressed air is supplied to the machine via the connection 12 in thebackhead and admission of this air is controlled by the actuatingthrottle valve 13. The valve in turn is controlled by the throttle lever1S, pivoted at 16, which shifts the link 17 to move the valve to theopen position. A spring 18 urges the valve to the closed position.

Air is ported through passage 19 to chamber 20 in the valve chest 21where it is diverted to either front chamber 22 via port 23, or to rearchamber 24 via port 2S.

An annular groove or port 27 is formed in the bore 28 which formschambers 22 and 24. Additional concentric bores 30, 31,32 and 33 areformed in series along the length of the housing 10.

becomes very hot and therefore diicult if not impossible to handle. Thisheat also adversely effects the wear life of certain parts. l

A general object of the present invention is to provide a pneumatic toolwhich overcomes the above mentioned difficulties.

In accordance with the present invention a pneumatic machine has beenprovided in which the exhaust air is directed through the front end ofthe machine where it emerges `at a reduced velocity and-is directedtoward the end of the tool. By so exhausting the air, dirt or otherforeign matter is prevented from entering the working parts, such asbetween the tool shank and the chuck, while the machine is operating.Any foreign matter that has entered the machine during an idle period ofthe tool will be immediately ejected when the machine is started becauseof the large volume of air exhausted past these parts.

The invention also contemplates the cooling of the front end of themachine by the exhaust air so as to enable the operator to firmly graspthe machine at allV times. This cooling is also effective to preventoverheating of the buffer parts and contributes to increased wear lifethereof.

Another aspect of the invention provides a pneumatic machine having afront end construction which permits ready removal and insertion of thetools therein, and which permits the use of a relatively small diametercylindrical shape, free of any projections, which can be convenientlyheld by the operator.

Theinvention furthermore provides a novel buier construction andassembly for such a machine which will absorb the shock of the hammerimpact on the tool when the tool is not in contact with the work, aswhen being withdrawn from the lwork.

These and other objects and advantages of the invention Will appearhereinafter as this disclosure progresses, reference being had to theaccompanying drawings in which:

Figure 1 is a longitudinal cross-sectional view of a machine made inaccordance with the present invention; and

A hammer 35 is reciprocable in bore 30 and has a piston 36 formedintegrally therewith which reciprocates within bore 28.

y The piston and hammer are reciprocated in the con-- ventiona-l mannerby alternately porting compressed air to the front and rear chambers 24and 22 respectively, by

the automatic operating valve 38. The compressed' air that is used toreciprocate the piston is exhausted to at mosphere via annular groove 27and passageway 40.

A chuck bushing 42 is mounted within bore 32 and the spade shank 43 hasa collar 44 which engages the rounded'.

end 45 of the bushing so as to be limited in its retraction. within thehousing. The hammer engages the inner end of the shank and' the outerend extends outwardly of the housing and has a spade portion 46 formedthereon.

The bore 33 contains the split stop ring 48 against which the collar 44strikes when moving in an outward direction. Another ring 49 is 4alsosecured in the bore and a resilient tubular-shaped buier 50 is heldcaptive in the bore between the rings 48 and 49.

f The rings 48, 49 and the buffer are held in assembled relationship bythe garter spring 51l which is snapped into its retainer groove 52.

The garter spring consists of a closely wound steel spring having coilswith little space therebetween. The ends of the spring are joined toform a continuous ring which makes assembly and disassembly convenient,but a continuous ring is not essential.

When the spring is snapped into the groove 52, about one-half. of itscoils are exposed for holding ring 49. This provides a substantiallycomplete circumferential bearing surface for positive retaining actionagainst ring 49. The ring 49 not only provides a solid backing for thebuffer 50 but also provides a good surface for action by the retainingspring.

The buffer serves to absorb the shock of the impact that occurs when thespade is struck by the hammer but is not in contact with the work. Sucha situation occurs when the tool is being Withdrawn from the work.

The spring snap ring, split ring and buffer assembly permits removal ofthese parts without the necessity for special tools. It is onlynecessary to insert a nail, screwdriver or other pointed object ineither slot 53 behind the ring 51 in order to remove it.

The outside configuration of the end of the housing can be maderelatively small and of smooth cylindrical shape which affords a surfacethat is easy to grip and hold for long periods of time.

The exhaust passageway 40 is in communication with past the buffer 50.This exhaust air not only prevents the ports from being overheated butalso keeps foreign matter from accumulating in the housing. The airpasses through areas of progressively larges cross section as it passesthrough to discharge and by the time it emerges from the machine, itsvelocity has been reduced considerably.

Another cross port 55 connects passage 40 with bore 31. Oil carried bythe air will thereby reach the chuck 42 and its adjacent associatedparts and thereby lubricate the same which facilitates the changing ofthe tools.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming theV subject matter which is regarded as theinvention.

I claim:

1. In la pneumatic machine having an axial bore therein and opening outone end thereof, a tool reciprocable in said bore within limits andextending freely through said bore and outwardly from said machine, anexhaust passageway extending substantially parallel to and laterally ofsaid bore, said passageway being in air exhausting communication withsaid axial bore whereby exhaust -air passes between said tool and saidbore for blowing foreign matter generally axially from said machine, theair flow capacity of the space between the bore and the tool beinggreater than that of said passageway.

2. In a pneumatic machine having an axial bore therein and opening outone end thereof, a resilient buier confined Within said bore, meansproviding positive bearing stops at opposite ends of said buffer andpreventing longitudinal displacement thereof, while permittingcompression between said limit stops, a tool reciprocable in said boreand extending freely through said buffer and outwardly from saidmachine, an exhaust passageway in air exhausting communication with saidaxial bore whereby exhausted air is directed between said tool and saidbuffer for blowing foreign matter axially from said ma\ chine and forcooling said buifer.

3. In a pneumatic machine having an axial bore there in and opening outone end thereof, a pair of steel rings mounted in said bore, atubular-shaped resilient buffer in said bore and between said rings, aretaining ring mount ed in said bore for holding said rings and buffercaptive in said bore, a tool reciprocable in said bore and extendingfreely through said buffer and outwardly from said machine, an exhaustpassageway in air exhausting communication with said axial bore abovesaid buffer whereby exhausted air is directed between said tool and saidbuffer for blowing foreign matter axially from said machine and forcooling said buffer.

4, In a pneumatic machine having a hammer reciprocable lin a housing byalternately porting compressed air to chambers on opposite sides of saidhammer, said housing having an axial bore therein and opening out oneend thereof, a resilient buffer securely mounted in said i' bore andretained against axial displacement therein, a

reciprocable tool engageable by said hammer and extending freely throughsaid buffer and outwardly from said housing, an exhaust passagewayextending longitudinally of the housing outwardly `of said bore andplacing said chambers in air exhausting communication with said axialbore above said buffer whereby air exhausted from said chambers passesbetween said tool and said buffer for blowing foreign matter axiallyfrom said housing and cooling said buffer.

5. In a pneumatic machine having 'a hammer reciprocable in a housing byalternately porting compressed air to chambers on opposite sides of saidhammer, said housing having an axial bore therein and opening out oneend thereof, a pair of steel rings mounted in said bore, atubular-shaped resilient buffer in said bore and between said rings, aretaining ring mounted in said bore for holding said rings and buffercaptive in said bore, a reciprocable tool engageable by said hammer andextending freely through said buffer and. outwardly from said housing,an exhaust passageway placing said chambers in air exhaustingcommunication with said axial bore above said buffer whereby airexhausted from said chambers passes between said tool and said bufferfor blowing foreign matter axially from said housing and cooling saidbuffer.

References Cited in the file of this patent UNITED STATES PATENTS1,391,629 Haight Sept. 20, 1921 1,481,643 Jimerson Ian. 22, 19241,787,178 Stevens Dec. 30, 1930 1,846,804 Hansen s Feb. 23, 19322,219,816 Mould Oct. 29, 1940 2,337,351 Schorer Dec. 12, 1943 2,500,669Docg Mar. 14, 1950 2,554,568 IGillerstrorn May 29, 1951 2,672,129Fischer Mar. 16, 1954 2,738,769 Holman et al. Mar. 20, 1956 kan...

